/*
*  linux/kernel/serial.c
*
*  (C) 1991  Linus Torvalds
*/

/*
*	serial.c
*
* This module implements the rs232 io functions
*	void rs_write(struct tty_struct * queue);
*	void rs_init(void);
* and all interrupts pertaining to serial IO.
*/

#include <linux\tty.h>
#include <linux\sched.h>
#include <asm\system.h>
#include <asm\io.h>

#define WAKEUP_CHARS (TTY_BUF_SIZE/4)

extern void rs1_interrupt(void);
extern void rs2_interrupt(void);

static void init(int port)
{
	outb_p(0x80, port + 3);	/* set DLAB of line control reg */
	outb_p(0x30, port);		/* LS of divisor (48 -> 2400 bps */
	outb_p(0x00, port + 1);	/* MS of divisor */
	outb_p(0x03, port + 3);	/* reset DLAB */
	outb_p(0x0b, port + 4);	/* set DTR,RTS, OUT_2 */
	outb_p(0x0d, port + 1);	/* enable all intrs but writes */
	(void)inb(port);		/* read data port to reset things (?) */
}

void rs_init(void)
{
	set_intr_gate(0x24, rs1_interrupt);
	set_intr_gate(0x23, rs2_interrupt);
	init(tty_table[1].read_q.data);
	init(tty_table[2].read_q.data);
	outb(inb_p(0x21) & 0xE7, 0x21);
}

/*
* This routine gets called when tty_write has put something into
* the write_queue. It must check wheter the queue is empty, and
* set the interrupt register accordingly
*
*	void _rs_write(struct tty_struct * tty);
*/
void rs_write(struct tty_struct * tty)
{
	cli();
	if (!EMPTY(tty->write_q))
		outb(inb_p((unsigned short)tty->write_q.data + 1) | 0x02, (unsigned short)tty->write_q.data + 1);
	sti();
}
